Electrode-assisted catalytic water oxidation by a flavin derivative

Abstract

The success of solar fuel technology relies on the development of efficient catalysts that can oxidize or reduce water. All molecular water-oxidation catalysts reported thus far are transition-metal complexes, however, here we report catalytic water oxidation to give oxygen by a fully organic compound, the N(5)-ethylflavinium ion, Et-Fl+. Evolution of oxygen was detected during bulk electrolysis of aqueous Et-Fl+ solutions at several potentials above +1.9 V versus normal hydrogen electrode. The catalysis was found to occur on glassy carbon and platinum working electrodes, but no catalysis was observed on fluoride-doped tin-oxide electrodes. Based on spectroelectrochemical results and preliminary calculations with density functional theory, one possible mechanistic route is proposed in which the oxygen evolution occurs from a peroxide intermediate formed between the oxidized flavin pseudobase and the oxidized carbon electrode. These findings offer an organic alternative to the traditional water-oxidation catalysts based on transition metals. So far, reports of molecular electrochemical water oxidation have involved catalytic transition metal complexes. Now it is demonstrated that water can be oxidized, and oxygen evolved, using a simple organic, flavin derivative.

Cite this article

Mirzakulova, E., Khatmullin, R., Walpita, J. et al. Electrode-assisted catalytic water oxidation by a flavin derivative. Nature Chem 4, 794–801 (2012). https://doi.org/10.1038/nchem.1439

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